Bond performance of corroded rebars in sustainable alkali-activated slag-based concrete incorporating steel fibers

In this study, the bond performance between corroded rebar and steel fiber reinforced alkaliactivated concrete (AAC) was investigated. The effects of the fiber content, corrosion degree, and rebar diameter were analyzed. The results showed a 30.7% enhancement in the bond strength by incorporating copper-coated steel fibers into AAC. The loss of copper increased the corrosioninduced bond strength degradation, which intensified with an increase in the fiber content. Steel fibers with a volume content of 0.5% were observed to be less susceptible to corrosion and could improve concrete brittleness and bond strength. A corrosion degree of 2% improved the bond by forming filled and frictional corrosion products, whereas a corrosion degree of 4% diminished it. The adverse impact of corrosion was more pronounced in rebars with smaller diameters owing to their lower rib heights. The established mesoscale finite-element model can accurately simulate the stress state of concrete and fibers. This paper proposes and validates an equation to determine the bond strength between fiber reinforced AAC and the corroded rebar by using testing results and literature data.